In October 2017, one of the Company’s tenants in Asia, Tata Teleservices Limited (“Tata Teleservices”), informed the Department of Telecommunications in India of its intent to exit the wireless telecommunications business and announced plans to transfer its business to another telecommunications provider. The Company will continue to monitor the status of these developments, as it is possible that the estimated future cash flows may differ from original estimates. Changes in estimated cash flows from Tata Teleservices could have an impact on previously recorded tangible and intangible assets, including amounts originally recorded as tenant-related intangibles, which have a current net book value of $445.0 million.

Fair Value of Financial Instruments—The Company’s financial instruments for which the carrying value reasonably approximates fair value at September 30, 2017 and December 31, 2016 include cash and cash equivalents, restricted cash, accounts receivable and accounts payable. The Company’s estimates of fair value of its long-term obligations, including the current portion, are based primarily upon reported market values. For long-term debt not actively traded, fair value is estimated using either indicative price quotes or a discounted cash flow analysis using rates for debt with similar terms and maturities. As of September 30, 2017 and December 31, 2016, the carrying value of long-term obligations, including the current portion, was $19.3 billion and $18.5 billion, respectively. As of September 30, 2017, the fair value of long-term obligations, including the current portion, was $19.8 billion, of which $12.0 billion was measured using Level 1 inputs and $7.8 billion was measured using Level 2 inputs. As of December 31, 2016, the fair value of long-term obligations, including the current portion, was $18.8 billion, of which $11.8 billion was measured using Level 1 inputs and $7.0 billion was measured using Level 2 inputs.

7. INCOME TAXES

The Company provides for income taxes at the end of each interim period based on the estimated effective tax rate (“ETR”) for the full fiscal year. Cumulative adjustments to the Company’s estimate are recorded in the interim period in which a change in the estimated annual ETR is determined. Under the provisions of the Internal Revenue Code of 1986, as amended, the Company may deduct amounts distributed to stockholders against the income generated by its REIT operations. The Company continues to be subject to income taxes on the income of its TRSs and income taxes in foreign jurisdictions where it conducts operations. In addition, the Company is able to offset certain income by utilizing its net operating losses, subject to specified limitations.

The Company provides valuation allowances if, based on the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. Management assesses the available positive and negative evidence to estimate if sufficient future taxable income will be generated to use the existing deferred tax assets.

As of September 30, 2017 and December 31, 2016, the total unrecognized tax benefits that would impact the ETR, if recognized, were approximately $107.4 million and $102.9 million, respectively. The amount of unrecognized tax benefits during the three and nine months ended September 30, 2017 includes additions to the Company’s existing tax positions of $1.9 million and $5.7 million, respectively, foreign currency fluctuations of $1.0 million and $3.7 million, respectively, and reductions due to the expiration of the statute of limitations in certain jurisdictions of $0.4 million during each of the three and nine months ended September 30, 2017. Unrecognized tax benefits are expected to change over the next 12 months if certain tax matters ultimately settle with the applicable taxing jurisdiction during this time frame, as described in note 12 to the Company’s consolidated financial statements included in the 2016 Form 10-K. The impact of the amount of these changes to previously recorded uncertain tax positions could range from zero to $11.5 million.

The Company recorded the following penalties and income tax-related interest expense during the three and nine months ended September 30, 2017 and 2016 (in thousands):

Three Months Ended September 30,

Nine Months Ended September 30,

2017

2016

2017

2016

Penalties and income tax-related interest expense

$

1,045

$

1,806

$

3,392

$

7,023

As of September 30, 2017 and December 31, 2016, the total amount of accrued income tax related interest and penalties included in the consolidated balance sheets was $28.9 million and $24.3 million, respectively.